Integrase is an enzyme produced by HIV so that the virus can multiply in the human body. GSK1349572 is a new drug in the integrase inhibitor class that prevents the enzyme from working properly and therefore prevents the virus from multiplying.

GSK1349572 has shown to be effective against viruses in a short-term monotherapy study in adults with no previous exposure to integrase inhibitors. The purpose of this study is to determine whether GSK1349572 is effective in the treatment of HIV-infected patients who no longer respond to treatment with the approved integrase inhibitor raltegravir and carry viruses with resistance to this drug. The safety and efficacy of GSK1349572 50mg once daily in combination with the background HIV drugs previously administered (unless discontinuation of a particular drug is required) will be assessed over 10 days (functional monotherapy phase), followed by the evaluation of the safety and efficacy of GSK1349572 given with a new optimised background regimen from Day 11 through at least Week 24.

Number of Participants Who Achieved HIV-1 RNA <400 Copies (c)/Milliliter (mL) or at Least 0.7 log10 c/mL Below Their Baseline Value at Day 11 [ Time Frame: Baseline (Day 1) and Day 11 ] [ Designated as safety issue: No ]

The number of participants who acheived Plasma Human Immunodeficiency Virus-1 (HIV-1) Ribonucleic Acid (RNA) <400 c/mL or at least 0.7 log10 c/mL below their Baseline value at Day 11 was assessed. The last observation was carried forward if a participant had missed the Day 11 visit. The Baseline observation was carried forward if a participant had discontinued the treatment before Day 11. Blood samples for assessment of HIV-1 RNA levels were collected at Baseline and Day 11.

Secondary Outcome Measures:

Mean Change From Baseline in Plasma HIV-1 RNA at Day 6 to 8, Day 11, and Weeks 4, 12, 24, 48, 72, and 96 [ Time Frame: Baseline; Day 6 to 8; Day 11; Weeks 4, 12, 24, 48, 72, and 96 ] [ Designated as safety issue: No ]

Mean change from Baseline in Plasma HIV-1 RNA was assessed on Day 6 to 8, Day 11, and Weeks 4, 12, 24, 48, 72, and 96 using data of the observed cases. Change from Baseline was calculated as the post-Baseline value minus the Baseline value.

The number of participants with plasma HIV-1 RNA <400 c/mL or <50 c/mL was assessed at Weeks 4, 12, 24, 48, 72, and 96 per the Food and Drug Administration's Time to Loss of Virological Response (TLOVR) algorithm. Using the TLOVR algorithm, participants are considered to have failed on therapy if they never achieved confirmed RNA levels below the threshold, if they had confirmed rebound of RNA above the threshold, if they made a non-permitted change in background regimen, or if they permanently discontinued investigational product for any reason.

The plasma DTG concentration immediately prior to dosing at steady state (C0) was assessed at Day 10, and Weeks 4 and 24. Blood samples for pharmacokinetic assessments were collected at pre-dose (within 15 minutes prior to dose).

Tmax of DTG [ Time Frame: Day 10 ] [ Designated as safety issue: No ]

The tmax is defined as the time of occurrence of the maximum plasma concentration (Cmax). The tmax was assessed at Day 10. Blood samples for pharmacokinetic assessments were collected at pre-dose (within 15 minutes prior to dose) and 2, 3, 4, 8, and 24 hours post-dose on Day 10 for DTG 50 mg OD and pre-dose (within 15 minutes prior to dose) and 2, 3, 4 and 8 hours post morning dose and 12 hours post evening dose for DTG 50 mg BID.

AUC is defined as the area under the DTG concentration-time curve as a measure of drug exposure. AUC(0-24) is defined as the area under the concentration-time curve from time zero (pre-dose) to 24 hours. AUC0-24 of DTG was assessed at Day 10. Blood samples for pharmacokinetic assessments were collected at pre-dose (within 15 minutes prior to dose) and 2, 3, 4, 8, and 24 hours post-dose on Day 10 for DTG 50 mg OD and pre-dose (within 15 minutes prior to dose) and 2, 3, 4 and 8 hours post morning dose and 12 hours post evening dose for DTG 50 mg BID.

Number of Participants With the Indicated HIV-1 Associated Conditions, Excluding Recurrences [ Time Frame: From the day of the first dose of study drug to the data cut-off (median 86 weeks for Cohort I, median 49 weeks for Cohort II ] [ Designated as safety issue: No ]

The number of participants with post-Baseline emergent HIV-1 disease progression (Acquired immunodeficiency syndrome (AIDS) or death) was assessed per the Centers for Disease Control and Prevention (CDC) 1993 revised classification system for HIV infection and expanded surveillance case definition for AIDS among adolescents and adults. The CDC classifies HIV infection as Category A (participants with asymptomatic HIV infection, acute HIV infection with accompanying illness, or persistent generalized lymphadenopathy), Category B (participants with symptomatic non-AIDS condition, i.e., conditions that are attributed to HIV infection or are indicative of a defect in cell-mediated immunity; or conditions are considered by physicians to have a clinical course or to require management that is complicated by HIV infection), and Category C (includes AIDS indicator conditions as defined by diagnostic or presumptive measures).

Number of Participants With HIV-1 Associated Disease Progression With the Indicated Shifts to CDC Class C or Death [ Time Frame: From the day of the first dose of study drug to the data cut-off (median 86 weeks for Cohort I, median 49 weeks for Cohort II ] [ Designated as safety issue: No ]

The number of participants with HIV-1 disease progression (AIDS or death) was assessed per the Centers for Disease Control and Prevention (CDC) 1993 revised classification system for HIV infection and expanded surveillance case definition for AIDS among adolescents and adults. The CDC classifies HIV infection as Category A (participants with asymptomatic HIV infection, acute HIV infection with accompanying illness, or persistent generalized lymphadenopathy), Category B (participants with symptomatic non-AIDS condition, i.e., conditions that are attributed to HIV infection or are indicative of a defect in cell-mediated immunity; or conditions are considered by physicians to have a clinical course or to require management that is complicated by HIV infection), and Category C (includes AIDS indicator conditions as defined by diagnostic or presumptive measures).

PDVF is defined in relation to Baseline plasma HIV-1 RNA levels: at Day 11, a decrease of <0.7 log10 c/mL unless <400 c/mL; at Weeks 8 to <16, a decrease of <1.0 log10 c/mL unless <400 c/mL or an increase of >= 1.0 log10 c/mL from nadir; and at or after Week 16, ≥400 c/mL. PDVF at Day 11 was based on a single plasma HIV-1 RNA evaluation and did not require confirmation. Confirmation testing was required for visits at or after Week 8. For the combination treatment phase, all HIV-1 RNA samples that meet a criterion for suspected PDVF must be confirmed by a second measurement performed at least 1 week but not more than 4 weeks apart from the date of the original sample.

Number of Participants With the Indicated Genotypic Resistance at Baseline [ Time Frame: Baseline ] [ Designated as safety issue: No ]

At Baseline, the integrase genotypic results were used to document resistance to raltegravir (RAL) and for the allocation of participants to one of two genotypic groups according to their RAL signature mutations to ensure a broad range of sensitivity to DTG. These results were not used to pre-define subgroup for analysis.

Median Fold Change in Sensitivity to DTG by the Baseline (Day 1) IN Mutational Group [ Time Frame: Baseline (Day 1) ] [ Designated as safety issue: No ]

Summary of median fold change in sensitivity to DTG by Integrase (IN) mutational group was assessed. The IN mutational group comprises of the following mutations: Q148 +2, Q148 +1, mixture (participants with virus containing more than one Y143, Q148 or N155 mutation at Day 1), Y143, N155, other (participants with virus having no mutations at codons 143, 148, or 155 at Day 1). Fold change (FC) is the fold change in 50% Inhibitory Concentration (IC50) relative to the wild-type control virus.

Number of Participants With the Indicated Treatment-emergent Integrase (IN) Mutations Detected at the Time of Protocol-defined Virologic Failure (PDVF) as a Measure of Genotypic Resistance [ Time Frame: From Baseline (Day 1) to the data cut-off (median 86 weeks for Cohort I, median 49 weeks for Cohort II) ] [ Designated as safety issue: No ]

An analysis of changes at specific amino acids in the IN coding region associated with resistance to raltegravir, elvitegravir, or DTG was performed at Day 1 and at the time of PDVF. PDVF is defined in relation to Baseline plasma HIV-1 RNA levels: at Day 11, a decrease of <0.7 log10 c/mL unless <400 c/mL; at Weeks 8 to <16, a decrease of <1.0 log10 c/mL unless <400 c/mL or an increase of >= 1.0 log10 c/mL from nadir; and at or after Week 16, ≥400 c/mL. PDVF at Day 11 was based on a single plasma HIV-1 RNA evaluation and did not require confirmation. Confirmation testing was required for visits at or after Week 8. For the combination treatment phase, all HIV-1 RNA samples that meet a criterion for suspected PDVF must be confirmed by a second measurement performed at least 1 week but not more than 4 weeks apart from the date of the original sample.

Number of Participants With the Indicated Fold Increase in DTG FC (Fold Change in IC50 Relative to Wild-type Virus) Between Baseline and the Time of PDVF, as a Measure of Post-Baseline Phenotypic Resistance [ Time Frame: From Baseline (Day 1) to the data cut-off (median 86 weeks for Cohort I, median 49 weeks for Cohort II) ] [ Designated as safety issue: No ]

The FC in IC50 (50% inhibitory concentration) for DTG relative to wild-type virus was determined for virus isolated at Baseline and at the time of PDVF. The number of participants with the indicated change (ratio) in the two values at the time of PDVF is presented. PDVF is defined in relation to Baseline plasma HIV-1 RNA levels: at Day 11, a decrease of <0.7 log10 c/mL unless <400 c/mL; at Weeks 8 to <16, a decrease of <1.0 log10 c/mL unless <400 c/mL or an increase of >= 1.0 log10 c/mL from nadir; and at or after Week 16, ≥400 c/mL. PDVF at Day 11 was based on a single plasma HIV-1 RNA evaluation and did not require confirmation. Confirmation testing was required for visits at or after Week 8. For the combination treatment phase, all HIV-1 RNA samples that meet a criterion for suspected PDVF must be confirmed by a second measurement performed at least 1 week but not more than 4 weeks apart from the date of the original sample.

Number of Participants With the Indicated Grade 3 and Grade 4 Clinical Chemistry Toxicities [ Time Frame: From the day of the first dose of study drug to the data cut-off (median 86 weeks for Cohort I, median 49 weeks for Cohort II) ] [ Designated as safety issue: No ]

Study (ING112961) is a Phase IIb, multicentre, open-label, single arm, two cohorts, pilot study to assess the antiviral activity of GSK1349572 containing regimen in HIV-1 infected ART-experienced adults with raltegravir (RAL) resistance. The study will include approximately 50 ART-experienced subjects with either current or past virologic failure to RAL. All subjects must harbour isolates with RAL resistance mutations at Screening. Subjects should also have documented genotypic and/or phenotypic resistance to at least one compound from each of three or more of the approved classes of ART (including integrase inhibitors [INIs]). Subjects with current RAL virologic failure will substitute RAL with GSK1349572 50mg once daily and continue the remaining components of their failing regimen through Day 10. Subjects with historical RAL virologic failure will add GSK1349572 50mg once daily to their failing regimen through Day 10. On Day 11 all subjects will continue GSK1349572 and optimize their background therapy. Antiviral activity, safety and tolerability of GSK1349572 will be evaluated at Day 11 and over time through at least Week 24.

ViiV Healthcare is the new sponsor of this study, and GlaxoSmithKline is in the process of updating systems to reflect the change in sponsorship.

Eligibility

Ages Eligible for Study:

18 Years and older

Genders Eligible for Study:

Both

Accepts Healthy Volunteers:

No

Criteria

Inclusion Criteria:

HIV-1 infected male or female adults at least 18 years of age with a plasma HIV-1 RNA > 1,000 copies/mL at study entry. Women capable of becoming pregnant must use appropriate contraception during the study (as defined by the protocol)

ART-experienced (defined as on stable ART for at least the last 2 months) and is either currently experiencing virologic failure to RAL or experienced virologic failure to RAL > 8 weeks prior to Screening

Must have documented RAL genotypic resistance on study entry genotype

Must have documented genotypic or phenotypic resistance to at least one drug from each of three or more of all approved classes of ART

For Cohort II, Subjects MUST be able to receive at least one fully active drug as part of the Day 11 optimised background regimen

Willing and able to understand and provide signed and dated written informed consent prior to screening

Exclusion Criteria:

Any pre-existing mental, physical, or substance abuse disorder which, which could compromise ability to comply with the protocol or compromise subject safety

Women who are pregnant or breastfeeding

An active AIDS-defining condition at the screening visit

Currently take and/or anticipated need for EFV, NVP, FPV/RTV or TPV/RTV during the study

Treatment with any of the following medications within 15 days of starting study drug, or anticipated to need, during the course of the study: Etravirine (unless co-administered with LPV/RTV or DRV/RTV), rifampin, rifabutin, phenytoin, phenobarbital, barbiturates, glucocorticoids, modafinil, oxcarbazepine, pioglitazone, troglitazone, carbamazepine, St. Johns wort

Previous participation in an experimental drug and/or vaccine trial(s) within 30 days or 5 half-lives

History of ongoing or clinically relevant pancreatitis or hepatitis within the previous 6 months

Expected to require treatment for HCV infection during the first 24 weeks of the study

Subject suffers from a serious medical condition which could compromise the safety of the subject.

Any condition that could interfere with the absorption, distribution, metabolism or excretion of the drug or render the subject unable to take oral medication

Screening lipase 3 times the upper limit of normal (ULN)

Any acute or Grade 4 laboratory abnormality at screening

Screening alanine aminotransferase (ALT) >5xULN

Screening ALT 3xULN and bilirubin 1.5xULN (with 35% direct bilirubin)

Personal or family history of prolonged QT syndrome.

Any clinically significant finding, as specified in the protocol, on screening or baseline electrocardiograph (ECG)

History of allergy to the study drugs or their components or drugs of their class

Treatment with radiation therapy or cytotoxic chemotherapeutic agents within 28 days prior to screening, or future need of treatment with these agents during the study

Treatment with immunomodulators within 28 days prior to screening or subject has received an HIV-1 vaccine within 90 days prior to screening

Contacts and Locations

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Please refer to this study by its ClinicalTrials.gov identifier: NCT00950859